The US prevalence of childhood-onset obesity and type 2 diabetes, both predictors of cardiovascular risk, have increased to epidemic proportions in recent decades. Children with mental illness, especially those treated with antipsychotic medications, are at additional risk for obesity (adiposity) and related risk conditions. A variety of noninvasive techniques to assess cardiometabolic risk have begun to be applied in children, including body composition measured with dual energy x-ray absorptiometry (DEXA), carotid intima media thickness (CIMT) measured by ultrasound, and hepatic triglyceride content (HTGC) measured by 1H Magnetic Resonance Spectroscopy (MRS). These measures allow for the early, noninvasive study of adiposity-related metabolic risk. The overall aim of this two-study research plan is to characterize the level of measurable risk using these sensitive markers in treated and untreated children with mental health disorders, and to evaluate the magnitude of change in risk that can be observed using these biomarkers in children receiving a well established behavioral weight-loss intervention.